1 files changed, 126 insertions, 0 deletions
diff --git a/servo/components/style/values/generics/rect.rs b/servo/components/style/values/generics/rect.rs
new file mode 100644
index 0000000000..e6358373d6
--- /dev/null
+++ b/servo/components/style/values/generics/rect.rs
@@ -0,0 +1,126 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! Generic types for CSS values that are composed of four sides.
+
+use crate::parser::{Parse, ParserContext};
+use cssparser::Parser;
+use std::fmt::{self, Write};
+use style_traits::{CssWriter, ParseError, ToCss};
+
+/// A CSS value made of four components, where its `ToCss` impl will try to
+/// serialize as few components as possible, like for example in `border-width`.
+#[derive(
+    Animate,
+    Clone,
+    ComputeSquaredDistance,
+    Copy,
+    Debug,
+    MallocSizeOf,
+    PartialEq,
+    SpecifiedValueInfo,
+    ToAnimatedValue,
+    ToAnimatedZero,
+    ToComputedValue,
+    ToResolvedValue,
+    ToShmem,
+)]
+#[repr(C)]
+pub struct Rect<T>(pub T, pub T, pub T, pub T);
+
+impl<T> Rect<T> {
+    /// Returns a new `Rect<T>` value.
+    pub fn new(first: T, second: T, third: T, fourth: T) -> Self {
+        Rect(first, second, third, fourth)
+    }
+}
+
+impl<T> Rect<T>
+where
+    T: Clone,
+{
+    /// Returns a rect with all the values equal to `v`.
+    pub fn all(v: T) -> Self {
+        Rect::new(v.clone(), v.clone(), v.clone(), v)
+    }
+
+    /// Parses a new `Rect<T>` value with the given parse function.
+    pub fn parse_with<'i, 't, Parse>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+        parse: Parse,
+    ) -> Result<Self, ParseError<'i>>
+    where
+        Parse: Fn(&ParserContext, &mut Parser<'i, 't>) -> Result<T, ParseError<'i>>,
+    {
+        let first = parse(context, input)?;
+        let second = if let Ok(second) = input.try_parse(|i| parse(context, i)) {
+            second
+        } else {
+            // <first>
+            return Ok(Self::new(
+                first.clone(),
+                first.clone(),
+                first.clone(),
+                first,
+            ));
+        };
+        let third = if let Ok(third) = input.try_parse(|i| parse(context, i)) {
+            third
+        } else {
+            // <first> <second>
+            return Ok(Self::new(first.clone(), second.clone(), first, second));
+        };
+        let fourth = if let Ok(fourth) = input.try_parse(|i| parse(context, i)) {
+            fourth
+        } else {
+            // <first> <second> <third>
+            return Ok(Self::new(first, second.clone(), third, second));
+        };
+        // <first> <second> <third> <fourth>
+        Ok(Self::new(first, second, third, fourth))
+    }
+}
+
+impl<T> Parse for Rect<T>
+where
+    T: Clone + Parse,
+{
+    #[inline]
+    fn parse<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self, ParseError<'i>> {
+        Self::parse_with(context, input, T::parse)
+    }
+}
+
+impl<T> ToCss for Rect<T>
+where
+    T: PartialEq + ToCss,
+{
+    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+    where
+        W: Write,
+    {
+        self.0.to_css(dest)?;
+        let same_vertical = self.0 == self.2;
+        let same_horizontal = self.1 == self.3;
+        if same_vertical && same_horizontal && self.0 == self.1 {
+            return Ok(());
+        }
+        dest.write_char(' ')?;
+        self.1.to_css(dest)?;
+        if same_vertical && same_horizontal {
+            return Ok(());
+        }
+        dest.write_char(' ')?;
+        self.2.to_css(dest)?;
+        if same_horizontal {
+            return Ok(());
+        }
+        dest.write_char(' ')?;
+        self.3.to_css(dest)
+    }
+}